fix(router): reuse quality savings metadata

litellm/router_strategy/adaptive_router/adaptive_router.py

@@ -224,12 +224,14 @@ class AdaptiveRouter:
         baseline = resolve_baseline(self.litellm_router_instance, self.config.available_models)
         if baseline is None:
             return {}  # mutable-ok: immutable empty result for unresolved baseline
-        fields: StandardLoggingRoutingDecision = {
+        return {
             "savings_baseline_model": baseline.model,
-        }  # mutable-ok: assemble TypedDict kwargs
-        if baseline.deployment_id is not None:
-            fields["savings_baseline_deployment_id"] = baseline.deployment_id
-        return fields
+            **(
+                {"savings_baseline_deployment_id": baseline.deployment_id}
+                if baseline.deployment_id is not None
+                else {}
+            ),
+        }
 
     # ---- Pick model ------------------------------------------------------
 

litellm/router_strategy/quality_router/quality_router.py

@@ -326,12 +326,14 @@ class QualityRouter(CustomLogger):
         baseline = resolve_baseline(self.litellm_router_instance, self.config.available_models)
         if baseline is None:
             return {}  # mutable-ok: immutable empty result for unresolved baseline
-        fields: StandardLoggingRoutingDecision = {
+        return {
             "savings_baseline_model": baseline.model,
-        }  # mutable-ok: assemble TypedDict kwargs
-        if baseline.deployment_id is not None:
-            fields["savings_baseline_deployment_id"] = baseline.deployment_id
-        return fields
+            **(
+                {"savings_baseline_deployment_id": baseline.deployment_id}
+                if baseline.deployment_id is not None
+                else {}
+            ),
+        }
 
     async def async_pre_routing_hook(
         self,
@@ -348,6 +350,9 @@ class QualityRouter(CustomLogger):
             verbose_router_logger.debug("QualityRouter: No messages provided, skipping routing")
             return None
 
+        conversation_continuing: Final = conversation_is_continuing(messages)
+        savings_fields: Final = self._savings_fields()
+
         # Extract last user message and last system prompt — same rules as
         # ComplexityRouter.async_pre_routing_hook.
         user_message: str | None = None
@@ -376,9 +381,9 @@ class QualityRouter(CustomLogger):
                 router_type="quality",
                 routed_model=self.config.default_model,
                 cause="default_fallback",
-                conversation_continuing=conversation_is_continuing(messages),
+                conversation_continuing=conversation_continuing,
             )
-            default_routing_decision.update(self._savings_fields())
+            default_routing_decision.update(savings_fields)
             return PreRoutingHookResponse(
                 model=self.config.default_model,
                 messages=messages,
@@ -405,7 +410,7 @@ class QualityRouter(CustomLogger):
                     "matched_keyword": matched_keyword,
                     "quality_tier": self._model_quality.get(routed_model),
                     "complexity_tier": None,
-                    "conversation_continuing": conversation_is_continuing(messages),
+                    "conversation_continuing": conversation_continuing,
                 },
             )
             keyword_routing_decision: Final = StandardLoggingRoutingDecision(
@@ -414,9 +419,9 @@ class QualityRouter(CustomLogger):
                 routed_model=routed_model,
                 cause="keyword",
                 matched_keyword=matched_keyword,
-                conversation_continuing=conversation_is_continuing(messages),
+                conversation_continuing=conversation_continuing,
             )
-            keyword_routing_decision.update(self._savings_fields())
+            keyword_routing_decision.update(savings_fields)
             keyword_quality_tier: Final = self._model_quality.get(routed_model)
             if keyword_quality_tier is not None:
                 keyword_routing_decision["tier"] = str(keyword_quality_tier)
@@ -454,7 +459,7 @@ class QualityRouter(CustomLogger):
                 "matched_keyword": None,
                 "quality_tier": int(quality_tier),
                 "complexity_tier": complexity_name,
-                "conversation_continuing": conversation_is_continuing(messages),
+                "conversation_continuing": conversation_continuing,
             },
         )
 
@@ -466,9 +471,9 @@ class QualityRouter(CustomLogger):
             tier=str(int(quality_tier)),
             score=score,
             signals=list(signals),
-            conversation_continuing=conversation_is_continuing(messages),
+            conversation_continuing=conversation_continuing,
         )
-        quality_routing_decision.update(self._savings_fields())
+        quality_routing_decision.update(savings_fields)
         return PreRoutingHookResponse(
             model=routed_model,
             messages=messages,

tests/test_litellm/router_strategy/test_quality_router.py

@@ -822,6 +822,27 @@ class TestKeywordOverride:
 
 
 class TestDecisionMetadata:
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize("content, cause", [("hi", "quality_tier"), ("write python", "keyword")])
+    async def test_conversation_shape_is_read_once_for_metadata_and_savings(self, keyword_router, content, cause):
+        class CountedMessage(dict):
+            role_reads = 0
+
+            def get(self, key, default=None):
+                if key == "role":
+                    self.role_reads += 1
+                return super().get(key, default)
+
+        message = CountedMessage(role="user", content=content)
+        kwargs: Dict[str, Any] = {}
+        response = await keyword_router.async_pre_routing_hook("qr", kwargs, [message])
+
+        assert response is not None
+        assert response.routing_decision["cause"] == cause
+        assert response.routing_decision["conversation_continuing"] is False
+        assert kwargs["metadata"]["quality_router_decision"]["conversation_continuing"] is False
+        assert message.role_reads == 2
+
     @pytest.mark.asyncio
     async def test_decision_includes_savings_baseline_and_conversation_shape(self, quality_router):
         quality_router.litellm_router_instance.model_name_to_deployment_indices = {

tests/test_litellm/router_strategy/test_savings_baseline.py

@@ -4,6 +4,7 @@ from litellm.router import Router
 from litellm.router_strategy.savings_baseline import (
     Baseline,
     canonical_model,
+    conversation_is_continuing,
     _models_in,
     _most_expensive,
     resolve_baseline,
@@ -22,6 +23,19 @@ def parent() -> Router:
     )
 
 
+@pytest.mark.parametrize(
+    "messages, expected",
+    [
+        (None, True),
+        ([], True),
+        ([{"role": "user", "content": "hello"}], False),
+        ([{"role": "user"}, {"role": "assistant"}, {"role": "user"}], True),
+    ],
+)
+def test_conversation_shape_for_savings(messages, expected):
+    assert conversation_is_continuing(messages) is expected
+
+
 class TestCanonicalModel:
     def test_qualifies_a_bare_name_with_the_provider_that_owns_it(self):
         assert canonical_model("claude-opus-5") == "anthropic/claude-opus-5"